Method and device for monitoring and improving arteriogenesis
A method for determining an arteriovascular condition of a subject having an arterial blood flow is shown. The method involves determining a temporal progression of an instantaneous blood flow condition of the arterial blood flow as well as deriving a slew rate of the temporal progression during an increase of the temporal progression. In addition, an arteriovascular condition indicator device is shown, which comprises: an input for receiving an input signal representing an instantaneous arterial blood flow condition of a subject and a slew rate monitor connected to the input. A corresponding control device for providing an activation signal is also shown. The control device comprises a maximum detector connected to the slew rate monitor. A method for stimulation of arteriogenesis is also shown, wherein a temporal progression of an instantaneous blood flow condition is monitored, a slew rate of the temporal progression is derived, and the maximum of the slew rate is determined. An external pressure is applied repeatedly to the arteriovascular section in synchronization with the occurrence of the determined maximum.
1. A method for determining a measure of an arteriogenic capacity of a subject having an arterial blood flow, comprising:
determining a temporal progression of an instantaneous blood flow condition of the arterial blood flow;
deriving a slew rate of the temporal progression during an increase of the temporal progression;
determining the maximum of the slew rate (peak velocity increase (PVI));
determining red blood cell velocities in the arterial blood flow (vRBC); and
determining a relative pulse slope index (RPSI) by forming the quotient of the PVI and a mean of the vRBC in the arterial blood flow, wherein the measure of arteriogenic capacity is a monotone function determined by the RPSI,
outputting the measure of the arteriogenic capacity to an output element of an indicator device, thereby providing an indication of the arteriogenic capacity of the subject, and
activating an actuator element that applies an external pressure to the subject in response to the output of the measure of the arteriogenic capacity.
2. The method of claim 1 , wherein determining the temporal progression of the instantaneous blood flow condition comprises a step of measuring at least one of the following physical quantities: an instantaneous blood flowvelocity, an instantaneous fluid pressure or an instantaneous shearing force within an arteriovascular section of the subject, the method further comprising a step of determining the blood flow condition according to a predefined function of at least one of the physical quantities.
3. The method of claim 2 , wherein the value representing the maximum of the slew rate corresponds to (a) the maximum slew rate of the instantaneous blood flow velocity, (b) the maximum slew rate of the instantaneous fluid pressure, or (c) the maximum slew rate of the instantaneous shearing force, or (d) one of these maximum slew rates normalized by a mean value of the blood flow velocity, of the fluid pressure or of the shearing force or (e) one of these slew rates normalized by the ratio of the mean value of the blood flow velocity, of the fluid pressure or of the shearing force to the cross sectional diameter of the arteriovascular section or to a fraction thereof.
4. The method of claim 1 , wherein deriving the slew rate of the temporal progression comprises: determining the slew rate by deriving the progression of the blood flow condition with respect to time; or determining the slew rate by relating an increase of the progression to the distance of time spanned by the increase.
5. The method of claim 1 , wherein the temporal progression is represented by a time-discrete blood flow condition signal comprising at least two values of the same positive slope or by a time-continuous blood flow condition signal comprising at least one positive slope.
6. The method of claim 1 , comprising repeatedly determining a variation of an arteriovascular condition with a repetition in time intervals greater than 5 days, wherein the variation of the arteriovascular condition is in monotone increasing relationship to a measure for an arteriogenic capacity of the subject reflecting the progress of an arteriovascular condition of the subject or reflecting a response on physical training of the subject; wherein the measure for the arteriogenic capacity is determined according to the variation and the relationship.
7. The method of claim 1 , wherein the vascular condition is determined by a plurality of consecutive individual arteriovascular condition determinations and by averaging the resulting individual arteriovascular conditions, or by identifying the maximum of the resulting individual arteriovascular conditions.
8. The method of claim 1 , wherein determining a temporal progression of a blood pressure quantity comprises measuring blood flow properties within an arteriovascular section of the subject by laser Doppler velocimetry, sonography or magnetic resonance imaging of the arteriovascular section, or by pressure sensoring according to wrist blood pressure monitoring, finger blood pressure monitoring, sphygmomanometry, plethysmometry, plethysmography, or intravascular blood pressure sensing, or impedance measurements of tissue or at the arteriovascular section or at a myocardial section.